The present invention relates to a deck fitting to be mounted on a supporting surface such as the deck or hatch of a ship.
Containers on a ship are liable to get out of position or collapse during transit if they are merely rested on the supporting surface of a ship.
FIG. 1 shows an ordinary arrangement for securing a container A. This arrangement includes positioning cones 1 and lashing terminals 2 fixed on the supporting surface of a freighter. The container is positioned by the positioning cones 1 inserted into holes provided at the four corners of its undersurface. One end of a stay 4 adapted to be tightened by a turnbuckle is secured in a hole 3 provided at each of the upper four corners of the container, while its other end is secured to the lashing terminal 2.
Because they are fixed on and protrude from the supporting surface, the conventional positioning cones 1 and lashing terminals 2 have the disadvantage that they hinder the cargo-handling carts from running on the supporting surface and are liable to be damaged by the cargo-handling carts colliding therewith. In order to eliminate the above-described disadvantage, the Japanese laid-open publication No. 51-37781 provides a deck socket comprising a fixed coupling member in the form of a socket secured to the supporting surface and a detachable coupling member such as a positioning cone or a lashing terminal adapted to be received in the fixed coupling member. Only when the freighter is loaded with containers, the detachable coupling member is attached to the fixed coupling member. The detachable coupling member is prevented from slipping out of the fixed coupling member by a plurality of claws provided on the fixed coupling member and adapted to engage with a plurality of claws provided on the detachable coupling member. The trouble is that the claws are susceptible to damage because they are not strong enough to withstand a sudden jerk given to the detachable coupling member. In addition, it is practically difficult to precisely machine both the fixed and detachable coupling members so as to allow all the claws to undergo even load. Therefore, a specific one of these claws is liable to be damaged.